This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -3 |
| 2 | 9 |
| 3 | -45 |
| 4 | 585 |
| 5 | -21105 |
| 6 | 1858185 |
| 7 | -367958745 |
| 8 | 157169540745 |
| 9 | -141321010837545 |
| 10 | 263377249955934345 |
| 11 | -1006907528155404620745 |
| 12 | 7840649068128410073284745 |
| 13 | -123736566059916445807102676745 |
| 14 | 3943516183297402946604761210564745 |